It is known to combine a blender with an ice shaver in a single unit, as disclosed for example in U.S. Pat. Nos. 6,793,167 and 8,282,268. Such units are used in restaurants and bars to produce frozen drinks. The restaurants and bars are often in warm and humid locations where frozen drinks are desirable.
The ice shaver functionality may be provided by an ice-receiving hopper at an upper region of the appliance that contains a rotating blade set and a fixed blade adjacent an exit chute, wherein the rotating blade set moves ice cubes over the fixed blade to shave the ice such that the ice shavings exit the hopper downwardly through the chute for receipt by a blender cup positioned below the chute. A d.c. brushless motor for driving the rotating blade set may be arranged below the hopper, wherein a drive shaft of the motor is drivably connected to a rotary shaft of the blade set.
Because the shaver blade set is situated in ice, heat is conducted out of the motor via the drive shaft. As a result, condensation forms within the motor housing. Condensation also forms on the drive shaft and may migrate toward the motor below. Melting ice arranged directly above the motor may also migrate to the motor. Although the motor housing and drive shaft bearings are sealed by O-rings, water may penetrate into the motor over time. Penetration becomes more likely as the sealing O-rings wear. Exposure to cleaning agents can accelerate wear of these seals. Penetration of water into the motor's stator and electronic sensing circuitry may cause motor failure, or at least may shorten the lifespan of the motor.
In current shaver motors, both the Hall sensor circuit board and the stator are encased in epoxy. However, water still manages to wick through the epoxy coating over time and damage the Hall effect sensor system (i.e., the motor's feedback system) and/or the stator windings.
In some units, the motor is positioned away from a location directly underneath the shaver blade to reduce exposure to water. However, this approach does not eliminate exposure to water, it requires more space, and it adds complexity by requiring mechanical elements (e.g. gears or belts) for transmitting rotational motion from the motor to the shaver blade.
What is needed is an improved motor design that provides better resistance to water damage.